Transient Dielectric Function of Fs-Laser Excited Bismuth

Author(s):  
Andrei V. Rode ◽  
Davide Boschetto ◽  
Thomas Garl ◽  
Antoine Rousse
Keyword(s):  
1997 ◽  
Vol 481 ◽  
Author(s):  
J. P. Callan ◽  
A. M.-T. Kim ◽  
L. Huangt ◽  
E. N. Glezer ◽  
E. Mazur

ABSTRACTWe use a new broadband spectroscopic technique to measure ultrafast changes in the dielectric function of a material over the spectral range 1.5–3.5 eV following intense 70-fs laser excitation. The results reveal the nature of the phase transformations which occur in the material following excitation. We studied the response of GaAs and Si. For GaAs, there are three distinct regimes of behavior as the pump fluence is increased — lattice heating, lattice disordering, and a semiconductor-to-metal transition.


Plasmonics ◽  
2016 ◽  
Vol 12 (6) ◽  
pp. 1813-1824 ◽  
Author(s):  
Luis J. Mendoza Herrera ◽  
David Muñetón Arboleda ◽  
Jesica M. J. Santillán ◽  
Marcela B. Fernández van Raap ◽  
Lucía B. Scaffardi ◽  
...  

2012 ◽  
Vol 112 (5) ◽  
pp. 054319 ◽  
Author(s):  
J. M. J. Santillán ◽  
F. A. Videla ◽  
M. B. Fernández van Raap ◽  
D. C. Schinca ◽  
L. B. Scaffardi

2001 ◽  
Vol 11 (PR2) ◽  
pp. Pr2-421-Pr2-424
Author(s):  
F. Zhong ◽  
L. Qin ◽  
J. Deng ◽  
X. Hu ◽  
Y. Zhu ◽  
...  
Keyword(s):  
X Ray ◽  

2015 ◽  
Vol 8 (2) ◽  
pp. 2148-2155 ◽  
Author(s):  
Abderrahim Benchaib ◽  
Abdesselam Mdaa ◽  
Izeddine Zorkani ◽  
Anouar Jorio

The vanadium dioxide is a material thermo chromium which sees its optical properties changing at the time of the transition from the phase of semiconductor state ↔ metal, at a critical temperature of 68°C. The study of the optical properties of a thin layer of VO₂ thickness 82 nm, such as the dielectric function, the index of refraction, the coefficient ofextinction, the absorption’s coefficient, the reflectivity, the transmittivity, in the photonic spectrum of energy ω located inthe interval: 0.001242 ≤ ω (ev) ≤ 6, enables us to control well its practical utility in various applications, like the intelligentpanes, the photovoltaic, paintings for increasing energy efficiency in buildings, detectors of infra-red (I.R) or ultra-violet(U.V). We will make simulations with Maple and compare our results with those of the literature


Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 114
Author(s):  
Chang Lu ◽  
Qingjian Lu ◽  
Min Gao ◽  
Yuan Lin

The reversible and multi-stimuli responsive insulator-metal transition of VO2, which enables dynamic modulation over the terahertz (THz) regime, has attracted plenty of attention for its potential applications in versatile active THz devices. Moreover, the investigation into the growth mechanism of VO2 films has led to improved film processing, more capable modulation and enhanced device compatibility into diverse THz applications. THz devices with VO2 as the key components exhibit remarkable response to external stimuli, which is not only applicable in THz modulators but also in rewritable optical memories by virtue of the intrinsic hysteresis behaviour of VO2. Depending on the predesigned device structure, the insulator-metal transition (IMT) of VO2 component can be controlled through thermal, electrical or optical methods. Recent research has paid special attention to the ultrafast modulation phenomenon observed in the photoinduced IMT, enabled by an intense femtosecond laser (fs laser) which supports “quasi-simultaneous” IMT within 1 ps. This progress report reviews the current state of the field, focusing on the material nature that gives rise to the modulation-allowed IMT for THz applications. An overview is presented of numerous IMT stimuli approaches with special emphasis on the underlying physical mechanisms. Subsequently, active manipulation of THz waves through pure VO2 film and VO2 hybrid metamaterials is surveyed, highlighting that VO2 can provide active modulation for a wide variety of applications. Finally, the common characteristics and future development directions of VO2-based tuneable THz devices are discussed.


2019 ◽  
Vol 3 (12) ◽  
Author(s):  
Stefana Anais Colibaba ◽  
Sabine Körbel ◽  
Carlo Motta ◽  
Fedwa El-Mellouhi ◽  
Stefano Sanvito

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 122
Author(s):  
Catharina Latz ◽  
Thomas Asshauer ◽  
Christian Rathjen ◽  
Alireza Mirshahi

This article provides an overview of both established and innovative applications of femtosecond (fs)-laser-assisted surgical techniques in ophthalmology. Fs-laser technology is unique because it allows cutting tissue at very high precision inside the eye. Fs lasers are mainly used for surgery of the human cornea and lens. New areas of application in ophthalmology are on the horizon. The latest improvement is the high pulse frequency, low-energy concept; by enlarging the numerical aperture of the focusing optics, the pulse energy threshold for optical breakdown decreases, and cutting with practically no side effects is enabled.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria Ruchkina ◽  
Dina Hot ◽  
Pengji Ding ◽  
Ali Hosseinnia ◽  
Per-Erik Bengtsson ◽  
...  

AbstractLaser-induced grating spectroscopy (LIGS) is for the first time explored in a configuration based on the crossing of two focused femtosecond (fs) laser pulses (800-nm wavelength) and a focused continuous-wave (cw) laser beam (532-nm wavelength). A thermal grating was formed by multi-photon absorption of the fs-laser pulses by $$\hbox {N}_{{2}}$$ N 2 with a pulse energy around 700 $$\upmu $$ μ J ($$\sim $$ ∼ 45 TW/$$\hbox {cm}^{2}$$ cm 2 ). The feasibility of this LIGS configuration was investigated for thermometry in heated nitrogen gas flows. The temperature was varied from room temperature up to 750 K, producing strong single-shot LIGS signals. A model based on the solution of the linearized hydrodynamic equations was used to extract temperature information from single-shot experimental data, and the results show excellent agreement with the thermocouple measurements. Furthermore, the fluorescence produced by the fs-laser pulses was investigated. This study indicates an 8-photon absorption pathway for $$\hbox {N}_{{2}}$$ N 2 in order to reach the $$\hbox {B}^{3}\Pi _{g}$$ B 3 Π g state from the ground state, and 8 + 5 photon excitation to reach the $$\hbox {B}^{2}\Sigma _{u}^{+}$$ B 2 Σ u + state of the $$\hbox {N}_{2}^{+}$$ N 2 + ion. At pulse energies higher than 1 mJ, the LIGS signal was disturbed due to the generation of plasma. Additionally, measurements in argon gas and air were performed, where the LIGS signal for argon shows lower intensity compared to air and $$\hbox {N}_{{2}}$$ N 2 .


2021 ◽  
Vol 27 (S1) ◽  
pp. 3086-3087
Author(s):  
Stephen Kelly ◽  
Robin White ◽  
Tobias Volkenandt ◽  
William Harris ◽  
Benjamin Tordoff ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document